World Champion Magnus Carlsen has defended one of his other World Championship titles, the World Rapidplay Champion, winning the 2015 event in Berlin. Leading going into the final day, Carlsen beat Zhigalko and Ivanchuk in the first 2 rounds, and after that the pack could not run him down.
While winning this title isn't a surprise, the fact that Carlsen has signed on to the Qatar Masters is. For a reigning World Champion to play in an Open Swiss (albeit one with a lower limit of 2300) is very unusual, as most top ranked players normally avoid risking rating pints against lower ranked opponents. But the growth in big money events (with good conditions) seems to be changing the attitude towards swisses (Millionaire Chess being an obvious example), so maybe his decision isn't as much a surprise as a recognition that the older way of doing things is changing.